overview of c++ language

Overview of C++ language

Lecture’s outline

What is C++?Identifiers.ConstantSemicolons & Blocks in C++Data typeCommentsOperatorDeclaration of variablesGiving value to variableC++ statements

prepared by Taif.A.S.G2

What is C++?• Developed by Bjarne Stroustrup (in 1979 at Bell Labs)

• C++ is regarded as a middle-level language, as it comprises a

combination of both high-level and low-level language features.

• C++ is a statically typed, compiled, general purpose, case-

sensitive, free-form programming language that supports

procedural, object-oriented, and generic programming.

• C++ is a superset of C that enhancement to the C language and

originally named C with Classes but later it was renamed C++.


identifiersThey are used for naming classes function, module,

variables, object in a program.

They follow the following rules:

1) They can have alphabets , digits, and the underscore(_).

2) They must not begin with a digit.

3) Uppercase and lowercase are distinct.

4) They can be of any length.

5) It should not be a keyword.


6) White space is not allowed.

ConstantConstant is one whose value cannot be changed after it has been initialized-any attempt to assign to field will produce a compile-error .So, we can declare the constant by using const field and use all uppercase letter.

Syntax of declare the constant is:

Example:

const int STRENGTH = 100;const float PI = 3.14;

const type name=value


Semicolons & Blocks in C++:• In C++, the semicolon is a statement terminator.

That is, each individual statement must be ended with a semicolon. It indicates the end of one logical entity.

• For example: following are two different statements:

x = y; y = y+1;

prepared by Taif.A.S.G 6

Data type


Comments

C++ can use both the single line comments and multi-line comments .single line comments begin with // and end at the end of line.For longer comments we can create multi-line comments by starting with /* and ending with */


Operator* / % + - are the mathematical operators* / % have a higher precedence than + or – ++ Increment operator –– Decrement operator

== Equal (careful)!= Not equal>= Greater than or equal<= Less than or equal> Greater than< Less than&& logical (sequential) and || logical (sequential) or= assignment


Logical operators

Relational operators

mathematical operators

Declaration of variables

The general form of declaration of variables:

Example:

int count;float x,y;double pi;char c1,c2,c3;byte b;

Type variable1, variable2,...., variableN;


Giving value to variable

The general form of giving value to variables:

Example:

finalValue=100;x=y=z=0;Yes = ‘x’;

variableName= value;


The general form of giving value to variables:

Example:

finalValue=100;x=y=z=0;Yes = ‘x’;

variableName= value;

Simple programs


Write C++ Program to find Sum and Average of two numbers?

Write C++ Program to find area of a circle?


C++ statement

Control statement

Selection statement

jump statement

iteration statement

If if-else switch for while do break continue return

• C++ supports the following statements Known as control or decision making statements.

1. if statement.2. switch statement.3. Conditional operator ? : statement.


Decision making


Decision making with if statement

The general form of simple if statement is :

Example:

if (a > b) cout<<"a > b";

if (<conditional expression>)<statement action>


Decision making with if statement cont..

The general form of simple if else statement is :

Example:

if (a > b) cout<<" a > b"; else cout<<"a<b";

if (<conditional expression>)<statement action>else <statement action>


Decision making with if statement cont..

The general form of Multiple if else statement is :

Example:if (a > b) cout<<" a > b"; else if (a< b) cout<<"b > a";else cout<<" a=b";

if (<conditional expression>)<statement action>else if (<conditional expression>)<statement action>else <statement action>

• The if statement allows you to select one of two sections of code to execute based on a boolean value (only two possible values). The switch statement allows you to choose from many statements.


Decision making with switch statement

switch (expr) { case c1: statements // do these if expr == c1 break; case c2: statements // do these if expr == c2 break; case c3: case c4: // Cases can simply fall thru. statements // do these if expr == any of c's break; . . . default: // OPTIONALstatements // do these if expr != any above }


Decision making with switch statement cont..

The ? : Operator:


• can be used to replace if...else statements. It has the following general form:

Exp1 ? Exp2 : Exp3; Where Exp1, Exp2, and Exp3 are expressions. • The value of a ? expression is determined like this:

Exp1 is condition evaluated. If it is true, then Exp2 is evaluated and becomes the value of the entire ? expression. If Exp1 is false, then Exp3 is evaluated and its value becomes the value of the expression.

Simple programs


Write C++ Program to find Number is Positive or Negative?

Write C++ Program to find the Grade of student ?

Write C++ Program to check the day of week by using SWITCH-CASE?

LoopingThe C++ language provides three constructs for

performing loop operations, there are:1. The for statement.2. The while statement.3. The do statement.



Looping cont..The general form of for statement:

Example:for( x=0; x<=10; x++) {cout<<x;}

for (initialization; test condition; increment) { Body of loop }


Looping cont..The general form of while statement:

Example:x=0;while(x<=10) {cout<<x;x++; }

initialization; while(test condition) { Body of loop }


Looping cont..The general form of do statement:

Example:x=0;do{cout<<x;x++; }while(x<=10) ;

initialization; do { Body of loop } while(test condition);


Nested Loopingfor(num2 = 0; num2 <= 3; num2++){ for(num1 = 0; num1 <= 2; num1++) { cout<<num2 << " " <<num1; }}

Int num1 Int num2

0 0

1

2

3 end of loop

0 1

1

2

3 end of loop

0 2

1

2

3 end of loop

0 3

1

2

3 end of loop

4 End of loop

Functions

• A complex problem is often easier to solve by dividing it into several smaller parts(Modules), each of which can be solved by itself. This is called structured programming.

• In C++ Modules Known as Functions & Classes• main() then uses these functions to solve the

original problem.


Functions (cont..)

• C++ allows the use of both internal (user-defined) and external functions.

• External functions (e.g., abs, ceil, rand, sqrt, etc.) are usually grouped into specialized libraries (e.g., iostream, stdlib, math, etc.)


Function prototype• The function prototype declares the input and

output parameters of the function.

• The function prototype has the following syntax: <type> <function name>(<type list>);

• Example: A function that returns the absolute value of an integer is: int absolute(int);

• If a function definition is placed in front of main(), there is no need to include its function prototype.


Function Definition• A function definition has the following syntax:

<type> <function name>(<parameter list>){<local declarations> <sequence of statements> }

• For example: Definition of a function that computes the absolute value of an integer:

int absolute(int x){ if (x >= 0) return x; else return -x; }

• The function definition can be placed anywhere in the program. prepared by Taif.A.S.G 30

Function call

• A function call has the following syntax: <function name>(<argument list>)

Example: int distance = absolute(-5);


overview of c++ language

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overview of c language

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b cout b cout b

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